Two Ways to Increase the Pulse Duration of the Solid Pulse-Forming Line Based on Dispersion Analysis

Abstract

Solid dielectrics have been widely investigated as potential attractive candidates in compact portable pulsed-power systems. Slow-wave structure with good dispersion characteristics and broad transmission band can be used to increase the pulse duration while the size of pulse-forming line (PFL) decreases. In this paper, we present two different slow-wave structures, the tape helix for coaxial-line and the meander-line structure for the planar line, to increase the pulse duration of solid PFLs based on dispersion analysis. At first, the characteristic impedances, electric length, and dispersion curve of the PFL with the slow-wave structure are calculated by the electromagnetic dispersion theory. Based on the theoretical calculations, the PFLs are designed and simulated by the electromagnetic field tool. Finally, some test results on the PFLs are introduced. Currently, both the Al2O3 ( $\varepsilon _{r}= 9.3$ ) helical PFL and the glass–ceramic ( $\varepsilon _{r} = 225$ ) meander-line PFL can deliver a pulsewith 50-ns width, of which the dimension is $\phi ~67~{\mathrm{ mm}} \times 305$ mm and $95~{\mathrm{ mm}} \times 95~{\mathrm{ mm}}\times 4$ mm, respectively.